1. Field of the Invention
This invention relates in general to evacuated envelopes for receiving solar energy.
2. Description of the Prior Art
Many attempts have been made to provide apparatus for converting solar energy into either heat where it can be used or directly into electrical energy by using photovoltaic devices. Such devices when used in the earth's atmosphere, are subject to degradation due to environmental factors. Also, it is important that photovoltaic devices do not become overheated as "thermal runaway" will ultimately destroy the devices and their characteristics.